Changes in pneumococcal serotypes distribution and penicillin resistance in healthy children five years after generalization of PCV10.

OBJECTIVE

() nasopharyngeal carriage has significantly decreased after the generalization of pneumococcal vaccination worldwide. This study sought to investigate changes in carriage rates, serotype distribution and penicillin non-susceptibility following the generalization of 10-valent pneumococcal conjugate vaccine.

METHODS

A prospective study was conducted in Marrakesh, Morocco, between 2017 and 2018, among healthy children attending vaccination centers. We collected nasopharyngeal swabs and questionnaire data for each child. Using univariate logistic regression, we analyzed the association between carriage and various risk factors. Comparisons of serotype diversity and penicillin resistance between 2017 and 2018 and the period before introduction of vaccination (2008-2009, n = 660) were performed using Simpson index and the chi-squared test, respectively.

RESULTS

During 2017-2018, 515 children aged between 6 and 36 months participated. The carriage rate was 43.3%. Looking at the distribution serotypes, the rate of PCV10 serotypes rate was only 9.6%. Among non-vaccine serotypes, an increase in serotypes 6C/6D (22; 14%), 19B/19C (17; 10.8%), and 15B/15C (11; 7%) was observed. A particular increase in serotype diversity was also observed after the generalization of PCV10 (p < 0.001). non-susceptible to penicillin decreased, reaching a rate of 26.6% in 2017-2018.

CONCLUSION

The significant change in carriage, serotype distribution, and penicillin resistance highlights the effectiveness of the pneumococcal conjugate vaccine among children in Marrakesh, Morocco.